Designation:D6991−05(Reapproved2010)StandardTestMethodforMeasurementsofInternalStressesinOrganicCoatingsbyCantilever(Beam)Method1ThisstandardisissuedunderthefixeddesignationD6991;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thistestmethodcoverstheprocedureformeasurementsofinternalstressesinorganiccoatingsbyusingthecantilever(beam)method.1.2Thismethodisappropriateforthecoatingsforwhichthemodulusofelasticityofsubstrate(Es)issignificantlygreaterthanthemodulusofelasticityofcoating(Ec)andforwhichthethicknessofsubstrateissignificantlygreaterthanthicknessofcoating(seeNote4andNote5).1.3Thestressvaluesarelimitedbytheadhesionvaluesofcoatingtothesubstrateandbythetensilestrengthofthecoating,orboth.1.4ThevaluesstatedinSIunitsaretoberegardedasthestandard.Thevaluesgiveninparenthesesareforinformationonly.1.5Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesandtodeterminetheapplicabilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D823PracticesforProducingFilmsofUniformThicknessofPaint,Varnish,andRelatedProductsonTestPanelsD1186TestMethodsforNondestructiveMeasurementofDryFilmThicknessofNonmagneticCoatingsAppliedtoaFerrousBase(Withdrawn2006)3D1400TestMethodforNondestructiveMeasurementofDryFilmThicknessofNonconductiveCoatingsAppliedtoaNonferrousMetalBase(Withdrawn2006)33.Terminology3.1DefinitionsofTermsSpecifictoThisStandard:3.1.1cantilever,n—abeamormembersecurelyfixedatoneendandhangingfreeattheotherend.3.1.2deflection,n—thedisplacementofabeamfromitsoriginalpositionbyanappliedforce.3.1.2.1Discussion—Thedeflectionofthebeamisusedtomeasurethatforceactingonthetip.3.1.3internalstress,n—astresssystemwithinasolidth...
